Rubber blankets, when used in rotary printing machines, are subjected to stresses which occur as the rubber blanket cylinder rotates in contact with a plate cylinder. The result of such stresses is the build-up of a bead extending parallel to the axis of the cylinder, which, in due course, results in a lateral squeeze-out or escape of the trailing region of the edge portions of the rubber blanket. These stresses and strains within the rubber blanket may lead to partial failure of proper register. This is particularly noticeable in the region of the printing material which receives ink in the zones of the rubber blanket which tends to form the lateral escape or deflection regions.